In recent years, the practice of treating the exhaust gas from a combustion furnace with activated carbon has become a popular measure for preventing the public nuisance otherwise caused when exhaust gas containing oxides of sulfur and oxides of nitrogen is released into the atmosphere. Activated carbon is widely used to remove sulfur dioxide from exhaust gas. The activated carbon which has heretofore been used for the desulfurization of exhaust gas is generally a product obtained by forming powdered coal into spheres and is deficient in mechanical strength and susceptible to disintegration. Furthermore, the prior art activated carbon is unsatisfactory in its ability to adsorb sulfur dioxide. Accordingly, a large amount of the prior art adsorbent must be used to effect the desired desulfurization and consequently the size of the sulfur dioxide adsorption tower holding the adsorbent must be large in size.
Consequently, a need exists for an activated carbon having high mechanical strength and excellent SO.sub.2 and NO.sub.x adsorbing capability.